The Performance Analysis Dashboard displays metrics at different resolution levels, depending on the historical time range that's selected in the toolbar. Whenever you're viewing the Dashboard in either Sample mode or in History mode, for ranges of 30 minutes or less, the raw samples collected (detail data) display. This detail level data has a collection frequency of anywhere from 10 seconds to one minute, depending on the metric. As you expand the time range you are viewing, averages over the indicated resolution interval are shown.
|Default Time Range||Resolution|
|0 <= 30 min||Detail Data|
|30 min <= 8 hrs||2 minutes|
|3 hrs 20 min <= 36 hrs||10 minutes|
|12 hrs <= 5 days||30 minutes|
|2 days <= 20 days||2 hours|
|3 days 8 hrs <= 40 days||4 hours|
|10 days <= 1 year||1 days|
|20 days <= 2 years||2 days|
|30 days <= 3 years+||3 days|
Performance Analysis uses the SQL Sentry database to store all of the performance data it collects. Performance data is rolled up, or averaged based on the age of the data. Once data becomes old enough to move into the next range, it's represented by an average over the time. The default settings for data retention for the different resolutions are as follows:
|Resolution||Default Retention Length|
|Detail Data||3 days|
|2 min||5 days|
|10 min||10 days|
|30 min||20 days|
|2 hours||40 days|
|4 hours||60 days|
|1 day||1 year (365 days)|
|2 days||2 years (730 days)|
|3 days||3 years (1,095 days)|
- The data retention period can be customized for specific needs. For more information, see the SQL Sentry Data Capacity Planning article.
- Data viewed under the Processes tab follows the same data retention and resolution policies as outlined above for Performance Analysis.
- See the Monitoring Service Settings article for information on other data retention values which are controlled by settings on the Storage tab of Global Settings. These default values may be changed there. Data for:
A database administrator comes into work on Monday and wants to investigate a performance related issue that happened late Friday afternoon. Because detail data is retained for Three days (72 hours), they can access it using the most granular detail resolution ( 0 <= 30 min).
A database administrator wants to compare performance data for the last two months (60 days). The data needs to be compared using the values for the four-hour resolution, because that's the resolution available at 60 days by default.